I had this problem very recently and found that it was air in the system. After I got all the air out it blows so hot, even at -40C here in Alberta like it is right now, that I have to turn down the heat.
I waited till it was cool, opened the rad cap and added coolant till it would stop taking any, then run and add the same time. I found that giving the top rad hope some slight squeezes and taps let out a bunch of little bubbles out. Topped up the catch can and ran it. DONE!
Also the space right in front of the air box behind the head light is the perfect size to put your coolant bottle with whatever you have left in case you need it on the run. I keep mine there
